Honeywell RTH8500 Series User manual

Operating
Manual
RTH8500
Touchscreen Programmable Thermostat

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For assistance with this product please visit http://yourhome.honeywell.com
or call Honeywell Customer Care toll-free at 1-800-468-1502
BE CAREFUL! Never use sharp instruments, such as a pencil
or pen, to press touchscreen keys. To prevent damage to the
thermostat, always press keys with your fingertip.
® U.S. Registered Trademark.
US Patent No. 6,595,430 and other patents pending.
Copyright © 2006 Honeywell International Inc.
All rights reserved.

RTH8500
1
About your new thermostat
Thermostat features ..........................2
Programming at a glance..................3
Quick reference to controls ..............4
Quick reference to status display ....5
Programming & Operation
Clock setting ......................................6
Fan setting ........................................7
System setting....................................8
Using program schedules ................9
Program schedule overrides ..........12
Vacation hold ..................................14
Special features ..............................15
Screen cleaning ..............................16
Furnace filter reminder ....................17
Appendices
Battery replacement ........................18
In case of difficulty ..........................19
Limited warranty ..............................21
Table of contents
This thermostat is ready to go!
Your new thermostat is pre-
programmed and ready to go.
See page 3 to check settings.
CAUTION: EQUIPMENT DAMAGE
HAZARD. To prevent possible
compressor damage, do not operate
cooling system when outdoor
temperature is below 50°F (10°C).

Operating Manual
2
About your new thermostat
Congratulations! You’ve just purchased the world’s most advanced, easy-
to-use thermostat. It has been designed to give you many years of reliable
service and touchscreen climate control.
Features
• 7-day program schedules maximize comfort and economy.
• Armchair programming: Just pull thermostat from the wall to set schedules.
• EnergyStar®compliant to greatly reduce your heating/cooling expenses.
• One-touch temp control overrides program schedule at any time.
• Precise comfort control keeps temperature within 1°F of the level you set.
• Change/check reminders let you know when to replace filters and batteries.
• Large touchscreen display with backlight is easy to read — even in the dark.

RTH8500
3
This thermostat is ready to go!
Your new thermostat is pre-programmed and ready to go. All you have to
do is set the time and day. Then check the settings below and change if
needed:
1Set clock......................................................................................See page 6
2Select fan setting: Preset to Auto ........................To change, see page 7
3Select system setting: Preset to Heat ..................To change, see page 8
4Program schedules: Preset to energy-saving levels
while you’re at work or asleep (assumes you
wake at 6 am, leave at 8 am, return at 6 pm
and go to bed at 10 pm) ..................................To change, see pages 10-13
ONE-TOUCH TEMP CONTROL: You can override the program schedule at any time,
and manually adjust the temperature (see pages 12-14).

MON TUE WED THU FRI SAT SUN
HEAT
SYSTEM
SCHED HOLD CLOCK SCREEN MORE
AUTO
FAN
OK TO PICK MULTIPLE DAYS
Inside
70 Set To
Following
Schedule
70
AM
6:01
Operating Manual
4
Quick reference to controls
Press day(s) to set program schedule (see page 11)
Press to select fan
operation (see page 7)
Press to adjust
temperature settings
(see pages 11-14)
Press to set program
schedule (see page 11)
Press to override
program schedule
(see pages 12-14)
Press to set clock
(see page 6)
Press to lock keypad for 30
seconds to clean screen
(see page 16).
Press to select system
type (see page 8)
Press for more options
(select models only)

WED
HEAT
SYSTEM
SCHED HOLD CLOCK SCREEN MORE
AUTO
FAN
Inside
70 Set To
Following
Schedule
Recovery
70
AM
6:01
RTH8500
5
Quick reference to status display
Current inside temperature Current day of week Temperature setting
System setting
Fan setting
Smart Response®
Technology in effect
(see page 15)
Program schedule on
(does not display
when off)
Current time Other display messages:
•Cool On: Cooling system is activated
•Heat On: Heating system is activated
•Aux Heat On: Auxiliary heating system is activated
(heat pump systems only)

Operating Manual
6
Clock setting
To set the current time display,
press clock, then press or
to adjust the time. Press and
hold or to advance the time
more quickly.
Press DDOONNEEto save & exit (or press
CCAANNCCEELLto exit without changing
the time).
Note: The real-time clock should never
require adjustment since it automatically
updates for daylight savings time, and
stores all date/time information.
Note: To change the current week day
display, see System Setup in your
Installation Guide.
Press CCLLOOCCKK
Adjust time, then press DDOONNEE
SCHED HOLD CLOCK SCREEN MORE
AM
6:01
DONE CANCEL
AM
6:02

RTH8500
7
Fan setting
Press FFAANNto select fan operation:
•On: Fan is always on.
•Auto: Fan runs only when the heating
or cooling system is on.
WED
HEAT
SYSTEM
SCHED HOLD CLOCK SCREEN MORE
AUTO
FAN
Inside
70 Set To
Following
Schedule
70
AM
6:01
Press FFAANN

Operating Manual
8
System setting
Press the SSYYSSTTEEMMbutton to select:
•Heat: Thermostat controls only the
heating system.
•Cool: Thermostat controls only the
cooling system.
•Auto: Thermostat automatically
selects heating or cooling depending
on the indoor temperature.
•Off: Heating and cooling systems
are off.
•Em Heat (only for heat pumps with
auxiliary heat): Thermostat controls
Emergency and Auxiliary Heat.
Compressor is locked out.
WED
HEAT
SYSTEM
SCHED HOLD CLOCK SCREEN MORE
AUTO
FAN
Inside
70 Set To
Following
Schedule
70
AM
6:01
Note: The Auto and Em Heat
system settings may not appear,
depending on how your
thermostat was installed.